1. Field of the Invention
The invention relates to a color wheel and more particularly, this invention relates to a color wheel, which is used in projection technology.
2. Description of the Related Art
Currently, image projection systems have become popular items in the optoelectronic industry owing to multiple requirements of a system having large display area, small dimension, and thin, light composition.
The popular projection systems are divided into three types including a liquid crystal display (LCD) type, a liquid crystal on silicon (LCoS) type, and a digital light processing (DLP) type, wherein the single-panel LCoS and DLP types advantageously have simplified systems and the following description will take the DLP type as an example.
In a DLP projector, a digital control method and a reflection principle are adopted. For a SCR (Sequential Color Recapture) system, light rays are integrated or converged by a light integration rod and then pass through the color filter of the color wheel, which splits the light rays. The split light rays are then projected onto a digital micro-mirror device (DMD). In this technology, the DMD is used to replace the liquid crystal panel for representing images in the conventional liquid crystal projector. Since the DMD includes several movable micro-mirrors, driving electrodes may control the tilt angle and deflection time of each movable mirror. Then, the light rays may be projected to form an image by switching the reflection directions of the light rays.
In the DLP projector, different clamping mechanisms are used to fix the color wheel and the light integration rod in the DLP projector so that the relative position between the color wheel and the light integration rod may be controlled. In the projection system, the position of each optical device through which light rays pass relates to the overall imaging quality of the DLP projector. So, each optical device has to be precisely positioned. Furthermore, when the color wheel is a SCR color wheel, the alignment precision between the color wheel and the light integration rod is more highly required.
However, since the conventional color wheel and light integration rod are fixed to different clamping mechanisms, respectively, the relative position between the color wheel and the light integration rod has to be adjusted. In addition, the relative position between other optical devices and the color wheel and the light integration rod also has to be noted. Consequently, it is necessary to spend longer time to artificially adjust the relative position between the color wheel and the light integration rod as well as that between other optical devices and the color wheel and light integration rod. Meanwhile, the precision of correctly adjusting the relative position between the color wheel and the light integration rod also cannot be easily controlled, and the reproducibility is also poor.